Is there a way to restrict web surfing for children that is not complicated ?

I have 3 children and we have to constantly reformat the computer they use due to a popup that covers the whole screen. Is it possible to restrict web surfing so we can avoid this issue.|||The simplest of the solution is to create an "Limited User Account" on windows.


http://www.microsoft.com/protect/compute鈥?/a>





This will prevent the user from having admin rights and thus installing unwanted software.





You can enable "Content Advisor" in Internet Explorer to prevent kids from visiting unwanted sites.


http://www.microsoft.com/windows/ie/ie6/鈥?/a>








These two are the simplest options|||Havnt used it but it seems simple enough http://www1.k9webprotection.com/